Polyarteritis nodosa (PAN) as a paraneoplastic vasculitis is rarely described, especially in association with metastatic squamous cell carcinoma (SCC). Furthermore, only 5% of all PAN patients have central nervous system (CNS) involvement - almost exclusively in the form of cerebral infarction or intracerebral haemorrhage.
We report a patient presenting with a spectrum of neurological symptoms found to have multiple cerebral lesions on CT head. A subsequent whole body PET scan revealed widespread glucose avid lesions thought to represent metastatic disease from an unknown primary malignancy. In preparation for a brain biopsy steroid therapy was commenced, but after a dramatic improvement in symptoms, a repeat PET was performed. There was almost complete resolution of the widespread lesions. The remaining base of tongue lesion later proved to represent SCC. A diagnosis of paraneoplastic PAN was made.
We believe this is a world-first case of PAN in association with systemic and cerebral vasculitic lesions presumed to be metastatic malignancy, with steroid-induced resolution demonstrated on serial magnetic-resonance imaging (MRI) and positron-emission tomography (PET) scans.